The unit is clean and well maintained, located within a beautiful building with nice common areas. The furniture are all in new condition, and basic necessities are provided (e.g., toilet paper, towel, cutlery, plates, etc.), though you should check with the owner in advance if there is anything in particular you are looking for (e.g., there were no clothes hangers, hair dryer, cleaning equipment, etc.).
Note that you need to pay for the water, electricity, and internet separately, and the owner requires a deposit. Prior to checking in, the owner will ask you to sign a lease agreement. When you arrive at the building, go to the back door where the juristic office is located because the front door will not open to guests. You need to first register your face at the juristic office because both the building entrance and the elevators operate through facial recognition. You should also ensure you communicate the expected time of arrival because the juristic office is not open 24/7, and without a Thai SIM card, you wouldn't be able to contact the person on call to give you the keys. To avoid these issues, it's best that you check in before the evening. To retrieve the keys, you will be required to fill out a resident form at the juristic office.
There is a 7-Eleven right in front of the building, and for any larger purchases, you can go to the Tops Market, Donki Mall, or Big C Supercenter, which are all nearby. The gym is on the top floor, and the swimming pool is right underneath (there is also an open-air jacuzzi). Both are open 24/7 and have stunning views, especially at night. On the ground floor, there is also a coin-operated laundry room with a dryer if you prefer not to use the washer already in the unit.
The unit is located high enough for there to be good ventilation when you open the windows, and the air quality is better than other places I've been. The building is located at around a 15-20 minute walk from either the Ekkamai or Thong Lo BTS stations.
The owner is very communicative, so if you have any questions or issues, you can contact her, and she normally responds quickly.